1 files changed, 94 insertions, 0 deletions
diff --git a/test/scenario/video_stream_unittest.cc b/test/scenario/video_stream_unittest.cc
index 1f2cad7e8c..873ef639ba 100644
--- a/test/scenario/video_stream_unittest.cc
+++ b/test/scenario/video_stream_unittest.cc
@@ -9,6 +9,7 @@
  */
 #include <atomic>
 
+#include "test/field_trial.h"
 #include "test/gtest.h"
 #include "test/scenario/scenario.h"
 
@@ -169,5 +170,98 @@ TEST(VideoStreamTest, SendsFecWithFlexFec) {
   VideoSendStream::Stats video_stats = video->send()->GetStats();
   EXPECT_GT(video_stats.substreams.begin()->second.rtp_stats.fec.packets, 0u);
 }
+
+TEST(VideoStreamTest, SendsFecWithDeferredFlexFec) {
+  ScopedFieldTrials trial("WebRTC-DeferredFecGeneration/Enabled/");
+  Scenario s;
+  auto route =
+      s.CreateRoutes(s.CreateClient("caller", CallClientConfig()),
+                     {s.CreateSimulationNode([](NetworkSimulationConfig* c) {
+                       c->loss_rate = 0.1;
+                       c->delay = TimeDelta::Millis(100);
+                     })},
+                     s.CreateClient("callee", CallClientConfig()),
+                     {s.CreateSimulationNode(NetworkSimulationConfig())});
+  auto video = s.CreateVideoStream(route->forward(), [&](VideoStreamConfig* c) {
+    c->stream.use_flexfec = true;
+  });
+  s.RunFor(TimeDelta::Seconds(5));
+  VideoSendStream::Stats video_stats = video->send()->GetStats();
+  EXPECT_GT(video_stats.substreams.begin()->second.rtp_stats.fec.packets, 0u);
+}
+
+TEST(VideoStreamTest, ResolutionAdaptsToAvailableBandwidth) {
+  // Declared before scenario to avoid use after free.
+  std::atomic<size_t> num_qvga_frames_(0);
+  std::atomic<size_t> num_vga_frames_(0);
+
+  Scenario s;
+  // Link has enough capacity for VGA.
+  NetworkSimulationConfig net_conf;
+  net_conf.bandwidth = DataRate::KilobitsPerSec(800);
+  net_conf.delay = TimeDelta::Millis(50);
+  auto* client = s.CreateClient("send", [&](CallClientConfig* c) {
+    c->transport.rates.start_rate = DataRate::KilobitsPerSec(800);
+  });
+  auto send_net = {s.CreateSimulationNode(net_conf)};
+  auto ret_net = {s.CreateSimulationNode(net_conf)};
+  auto* route = s.CreateRoutes(
+      client, send_net, s.CreateClient("return", CallClientConfig()), ret_net);
+
+  s.CreateVideoStream(route->forward(), [&](VideoStreamConfig* c) {
+    c->hooks.frame_pair_handlers = {[&](const VideoFramePair& info) {
+      if (info.decoded->width() == 640) {
+        ++num_vga_frames_;
+      } else if (info.decoded->width() == 320) {
+        ++num_qvga_frames_;
+      } else {
+        ADD_FAILURE() << "Unexpected resolution: " << info.decoded->width();
+      }
+    }};
+    c->source.framerate = 30;
+    // The resolution must be high enough to allow smaller layers to be
+    // created.
+    c->source.generator.width = 640;
+    c->source.generator.height = 480;
+    c->encoder.implementation = CodecImpl::kSoftware;
+    c->encoder.codec = Codec::kVideoCodecVP9;
+    // Enable SVC.
+    c->encoder.layers.spatial = 2;
+  });
+
+  // Run for a few seconds, until streams have stabilized,
+  // check that we are sending VGA.
+  s.RunFor(TimeDelta::Seconds(5));
+  EXPECT_GT(num_vga_frames_, 0u);
+
+  // Trigger cross traffic, run until we have seen 3 consecutive
+  // seconds with no VGA frames due to reduced available bandwidth.
+  auto cross_traffic =
+      s.net()->StartFakeTcpCrossTraffic(send_net, ret_net, FakeTcpConfig());
+
+  int num_seconds_without_vga = 0;
+  int num_iterations = 0;
+  do {
+    ASSERT_LE(++num_iterations, 100);
+    num_qvga_frames_ = 0;
+    num_vga_frames_ = 0;
+    s.RunFor(TimeDelta::Seconds(1));
+    if (num_qvga_frames_ > 0 && num_vga_frames_ == 0) {
+      ++num_seconds_without_vga;
+    } else {
+      num_seconds_without_vga = 0;
+    }
+  } while (num_seconds_without_vga < 3);
+
+  // Stop cross traffic, make sure we recover and get VGA frames agian.
+  s.net()->StopCrossTraffic(cross_traffic);
+  num_qvga_frames_ = 0;
+  num_vga_frames_ = 0;
+
+  s.RunFor(TimeDelta::Seconds(40));
+  EXPECT_GT(num_qvga_frames_, 0u);
+  EXPECT_GT(num_vga_frames_, 0u);
+}
+
 }  // namespace test
 }  // namespace webrtc